Petroleum raw material for the production of chemical solvents, that is to say, cracking gas, is based upon its fuel value at the refinery.
The same applies to a large extent to stripped natural gas although in many refineries the amount available is far in excess of requirements, with the result that unless it can be sold for town gas enrichment or to neighboring industrial concerns, it is either burnt or allowed to escape into the air.
The petroleum industry appears to have been slow to appreciate the possibilities of petroleum as a raw material for chemical synthesis, for it is only within the last ten to fifteen years that any progress has been made at all.
The complexity of petroleum and the difficulty of separating pure products either for raw materials or as reaction products has tended to hold back development, particularly as little is still known of the chemistry of all but the simplest hydrocarbons.
As a result, most of the industrial development has been based upon the simplest members only, very little new chemistry being required. Naturally as these members are paraffins, the products so far available are chiefly alcohols, esters, ketones, ethers and chloro-compounds: Considerable work has been carried out on the conversion of the simple olefines into aromatic hydrocarbons, but with the possible exception of the suggested production of styrene and its polymers, these have been intended for fuel purposes solely